Distributed data management

ABSTRACT

In some examples, a system for managing distributed data can include a processor to detect an update notification from a client device to update a managing server, the update notification indicating that a remote server node is unavailable. The processor can also generate a comparison value by comparing a first time stamp to a second time stamp, wherein the first time stamp corresponds to a time at which the system receives the update notification from the client device and the second time stamp corresponds to a time the remote server node transmits a set of renewal data. Furthermore, the processor can determine that the comparison value indicates the remote server node is unavailable and remove the remote server node from the managing server.

BACKGROUND

The present disclosure relates to distributed data, and morespecifically, but not exclusively, to managing distributed data.

SUMMARY

According to an embodiment described herein, a system for distributeddata management can include a processor to send a distributed datarequest to a remote server node. The processor can also detect that aperiod of time elapses without receiving the requested distributed datafrom the remote server node and update a managing server by sending aserver message to the managing server indicating that the remote servernode is unavailable. Furthermore, the processor can send the distributeddata request to a second remote server node.

According to another embodiment, a system for managing distributed datacan include a processor to detect an update notification from a clientdevice to update a managing server, the update notification indicatingthat a remote server node is unavailable. The processor can alsogenerate a comparison value by comparing a first time stamp to a secondtime stamp, wherein the first time stamp corresponds to a time at whichthe system receives the update notification from the client device andthe second time stamp corresponds to a time the remote server nodetransmits a set of renewal data. Furthermore, the processor candetermine that the comparison value indicates the remote server node isunavailable and remove the remote server node from the managing server.

According to another embodiment, a computer program product fordistributed data management can include a computer readable storagemedium having program instructions embodied therewith, wherein thecomputer readable storage medium is not a transitory signal per se. Theprogram instructions can be executable by a processor to cause theprocessor to detect an update notification from a client device toupdate a managing server, the update notification indicating that aremote server node is unavailable. The program instructions can alsocause the processor to generate a comparison value by comparing a firsttime stamp to a second time stamp, wherein the first time stampcorresponds to a time at which the system receives the updatenotification from the client device and the second time stampcorresponds to a time the remote server node transmits a set of renewaldata. Furthermore, the program instructions can cause the processor todetermine that the comparison value indicates the remote server node isunavailable and remove the remote server node from the managing server.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 depicts a block diagram of an example computing system that canmanage distributed data according to an embodiment described herein;

FIG. 2 is a process flow diagram of an example method, implemented by amanaging server, that can manage distributed data according to anembodiment described herein;

FIG. 3 is a process flow diagram of an example method, implemented by aclient device, that can manage distributed data according to anembodiment described herein;

FIG. 4 is a tangible, non-transitory computer-readable medium that canmanage distributed data by a managing server according to an embodimentdescribed herein;

FIG. 5 is a tangible, non-transitory computer-readable medium that canmanage distributed data by a client device according to an embodimentdescribed herein;

FIG. 6 depicts an illustrative cloud computing environment according toan embodiment described herein; and

FIG. 7 depicts a set of functional abstraction layers provided by acloud computing environment according to an embodiment described herein.

DETAILED DESCRIPTION

As client devices increasingly rely on services provided by remoteservers, managing data for the client devices becomes more complex. Datastore systems are often composed of a cluster of servers that employreplication to provide high availability and durability of the clientdata. Although cluster servers are connected and can directlycommunicate with each other, the client device may not be able todetermine which servers belong to the cluster. In some embodiments, theclient device communicates with a load balancer or reverse proxy toscale back end servers or to provide services, such as caching, orauthentication and security, to a set of back end servers. In someembodiments, load balancers maintain an open connection with back endservers. Accordingly, the load balancers can automatically determine ifa back end server is no longer available. In other embodiments, such asin cloud and web based systems, a load balancer may not maintain an openconnection with back end servers. Rather, the back end servers mayprovide time to live packets to indicate to the load balancer that theback end servers are still available.

The techniques described herein minimize the time that outdated or staledata is returned to client devices by using external knowledge. Externalknowledge, as referred to herein, includes data obtained by clientdevices regarding remote server nodes or cluster servers that provide aservice. In some embodiments, when a client device detects that datacorresponding to the clustered servers is stale or outdated, the clientdevice can respond to a managing server in the cluster. Therefore, theclient device can update data regarding the clustered servers eventhough the client device is not an owner of the data or storage locationfor the data. The techniques enable updating data corresponding to aclustered server more frequently. For example, time to live messages canbe transmitted from remote server nodes to a managing server node at apredetermined frequency to indicate remote server availability. In someembodiments, techniques described herein enable a managing server todetect stale or outdated data prior to a time to live message expiring.

The embodiments described herein include techniques for managingdistributed data. In some examples, a client system can send a requestfor distributed data to a remote server node and detect that a period oftime elapses without receiving the distributed data from the remoteserver node. The client system can also update a managing server bysending a server message to the managing server indicating that theremote server node is unavailable. In some embodiments, the clientsystem can send a request for the data to a second remote server node.

The managing server described herein can detect an update notificationfrom a client system to update the managing server, the updatenotification indicating that a remote server node is unavailable. Themanaging server can also generate a comparison value by comparing afirst time stamp to a second time stamp, wherein the first time stampcorresponds to a time at which the managing server receives the requestfrom the client system and the second time stamp corresponds to a timethe remote server node transmits a set of renewal data. Furthermore, themanaging server can determine that the comparison value indicates theremote server node is unavailable, and remove any identifyinginformation for the remote server node from the managing server.

With reference now to FIG. 1, an example computing device is depictedthat can manage distributed data. The managing server 100 may be forexample, a server, desktop computer, laptop computer, tablet computer,or smartphone. In some examples, managing server 100 may be a cloudcomputing node. Managing server 100 may be described in the generalcontext of computer system executable instructions, such as programmodules, being executed by a computer system. Generally, program modulesmay include routines, programs, objects, components, logic, datastructures, and so on that perform particular tasks or implementparticular abstract data types. Managing server 100 may be practiced indistributed cloud computing environments where tasks are performed byremote processing devices that are linked through a communicationsnetwork. In a distributed cloud computing environment, program modulesmay be located in both local and remote computer system storage mediaincluding memory storage devices.

The managing server 100 may include a processor 102 that is adapted toexecute stored instructions, a memory device 104 to provide temporarymemory space for operations of said instructions during operation. Theprocessor can be a single-core processor, multi-core processor,computing cluster, or any number of other configurations. The memory 104can include random access memory (RAM), read only memory, flash memory,or any other suitable memory systems.

The processor 102 may be connected through a system interconnect 106(e.g., PCI®, PCI-Express®, etc.) to an input/output (I/O) deviceinterface 108 adapted to connect the managing server 100 to one or moreI/O devices 110. The I/O devices 110 may include, for example, akeyboard and a pointing device, wherein the pointing device may includea touchpad or a touchscreen, among others. The I/O devices 110 may bebuilt-in components of the managing server 100, or may be devices thatare externally connected to the managing server 100.

The processor 102 may also be linked through the system interconnect 106to a display interface 112 adapted to connect the managing server 100 toa display device 114. The display device 114 may include a displayscreen that is a built-in component of the managing server 100. Thedisplay device 114 may also include a computer monitor, television, orprojector, among others, that is externally connected to the managingserver 100. In addition, a network interface controller (NIC) 116 may beadapted to connect the managing server 100 through the systeminterconnect 106 to the network 118. In some embodiments, the NIC 116can transmit data using any suitable interface or protocol, such as theinternet small computer system interface, among others. The network 118may be a cellular network, a radio network, a wide area network (WAN), alocal area network (LAN), or the Internet, among others. A clientcomputing device 120 may connect to the managing server 100 through thenetwork 118. In some examples, client computing device 120 can send arequest for distributed data to a remote server node 122. The clientcomputing device 120 can also detect that a period of time elapseswithout receiving the distributed data from the remote server node andupdate a managing server by sending a server message to the managingserver indicating that the remote server node is unavailable. A servermessage, as referred to herein, can indicate that a remote server nodeis no longer able to process distributed data requests. Furthermore, theclient computing device 120 can send the distributed data request forthe distributed data to a second remote server node. In someembodiments, a remote server node 122 may be an external webserver suchas a cloud computing node or a server in a clustered computingenvironment.

The processor 102 may also be linked through the system interconnect 106to a storage device 124 that can include a hard drive, an optical drive,a USB flash drive, an array of drives, or any combinations thereof. Insome examples, the storage device may include a message manager 126, aserver manager 128, and a server database 130. In some embodiments, themessage manager 126 can detect an update notification from a client toupdate the managing server or managing server 100, the updatenotification indicating that a remote server node is unavailable. Insome embodiments, the message manager 126 can also generate a comparisonvalue by comparing a first time stamp to a second time stamp, whereinthe first time stamp corresponds to a time at which the system receivesthe request from the client and the second time stamp corresponds to atime the remote server node transmits a set of renewal data.Furthermore, the server manager 128 can determine that the comparisonvalue indicates the remote server node is unavailable and remove remoteserver node data from the managing server. In some embodiments, themanaging server includes the server database 130, which includes a listof available remote server nodes that can process requests fordistributed data. The server database 130 may include any suitableidentifying information for each remote server node such as an internetprotocol address, machine identifier, media access control address, andthe like.

It is to be understood that the block diagram of FIG. 1 is not intendedto indicate that the managing server 100 is to include all of thecomponents shown in FIG. 1. Rather, the managing server 100 can includefewer or additional components not illustrated in FIG. 1 (e.g.,additional memory components, embedded controllers, modules, additionalnetwork interfaces, etc.). Furthermore, any of the functionalities ofthe message manager 126, the server manager 128, and the server database130 may be partially, or entirely, implemented in hardware and/or in theprocessor 102. For example, the functionality may be implemented with anapplication specific integrated circuit, logic implemented in anembedded controller, or in logic implemented in the processor 102, amongothers. In some embodiments, the functionalities of the message manager126, the server manager 128, and the server database 130 can beimplemented with logic, wherein the logic, as referred to herein, caninclude any suitable hardware (e.g., a processor, among others),software (e.g., an application, among others), firmware, or any suitablecombination of hardware, software, and firmware.

FIG. 2 is a process flow diagram of an example method that can managedistributed data for a client device. The method 200 can be implementedwith any suitable computing device, such as the client device 120 ofFIG. 1.

At block 202, a client device can send a distributed data request to aremote server node. For example, the client device can be a consumerclient that is to request distributed data from a managing server, whichcan forward the distributed data request to any suitable remote servernode. Distributed data, as referred to herein, can include anyinformation or data used to contact a clustered server or remote servernetwork. In some embodiments, any suitable number of remote server nodescan receive and process the distributed data request. For example, theremote server nodes may be interconnected using clustering techniques toenable providing a distributed service (also referred to as a cloudservice). Accordingly, the distributed data can correspond to a serviceprovided by a remote server node.

In some examples, the requested distributed data corresponds to aservice provided by a remote server node. For example, the client devicecan send a stream of distributed data requests using messages and astateless protocol to a remote server node to access a data storageservice. The messages arrive at a front-end server (also referred toherein as a managing server), which selects one remote server node orcluster member from a pool of remote server nodes that are implementingthe data storage service. In some examples, each message can correspondto any suitable data stored in the data storage service.

In some embodiments, messages sent directly by a client device to aremote server node can correspond to various actions. For example, amessage can correspond to a client device establishing distributed data.In some examples, a client device establishes distributed data bytransmitting the data to a data storage service at a local client timeT. A remote server node can assign the data a unique identifier andreturn the identifier and a time to live (TTL) timestamp thatcorresponds to a time period rather than a particular clock time. TheTTL timestamp can indicate a predetermined maximum period of time that aremote server node can store the distributed data. In some embodiments,the client device can send a renewal message before the TTL timestampexpires. Data for which the TTL has expired without receiving a renewalmessage can expire and be deleted from the remote server nodes.

In some embodiments, messages can also correspond to renewing data inwhich a remote server node indicates to a managing server that theremote server node requests to extend the lifetime of previously saveddata. In some examples, the managing server may allow or fail theoperation. In the case of successful completion, the remote server nodeis guaranteed that the data can remain valid for another time periodequal to the TTL timestamp.

Still referring to block 202, in some embodiments, the messages can alsocorrespond to deleting data in which a remote server node notifies amanaging server that the remote server node no longer needs data to bestored starting at the given time stamp. In some embodiments, themessages can also correspond to reading data from a data storageservice. For example, a remote server node can return the current datawith the current time stamp stored in its storage to the client device.

In some embodiments, the managing server can employ any suitableselection policy. Therefore, any remote server node may receive anymessage. Specifically, read messages and delete messages can be directedto a remote server node that did not receive the establish message. Insome examples, the data sharing model follows single writer and multiplereaders in which the service providing instance is responsible formanipulating the service's state. The messages transmitted from theclient device to the remote server node are managed by a managing serverdescribed in greater detail below in relation to FIG. 3.

At block 204, the client device can detect that a period of time elapseswithout receiving the distributed data from the remote server node. Forexample, the client device can detect that a threshold period of timehas been exceeded following the transmission of the distributed datarequest. In some embodiments, the threshold period of time correspondsto a maximum allowed time allotted to the remote server node forprocessing the request for distributed data and providing the requesteddistributed data to the client device.

At block 206, the client device can update a managing server by sendinga server message to the managing server indicating that the remoteserver node is unavailable. For example, in response to detecting that aremote server node has failed to provide requested distributed datawithin the threshold period of time, the client device can send a servermessage to a managing server. The server message can include anysuitable identifier for a remote server node that has failed to providerequested distributed data. For example, the server message can indicatean internet protocol (IP) address for the remote server node, a machineidentifier, a media access control (MAC) address, and the like. In someembodiments, the server message results in a managing server updating alist of available remote server nodes. For example, the server messagecan result in a managing server deleting an unresponsive remote servernode from the managing server or server database. The server message canprevent additional client devices from attempting to request data froman unresponsive remote server node.

In some embodiments, the server message can result in a managing serversetting a flag corresponding to a remote server, wherein the flagindicates that the remote server may not be available. In some examples,the managing server may delete a remote server node from the managingserver in response to a number of client devices indicating that theremote server node is unresponsive. In some embodiments, the managingserver may wait until the number of client devices indicating that theremote server node is unresponsive exceeds a threshold value within aperiod of time before deleting the remote server node from the managingserver.

At block 208, the client device can send the request for the distributeddata to a second remote server node. For example, the client device canresend the distributed data request to a managing server. The managingserver can forward the distributed data request to a second remoteserver node in response to the client device querying the managingserver for the second remote server node. In some examples, the clientdevice can also detect a second remote server node from a predeterminedlist of remote server nodes stored on the client device. In someembodiments, the client device can detect an indication from a managingserver that the requested distributed data is no longer available by anyremote server node. For example, the unavailable remote server node mayhave deleted the requested distributed data prior to becomingunavailable.

In some embodiments, the client device can detect the second remoteserver node from a list of prioritized remote server nodes. The list ofprioritized remote server nodes can be organized based on flagsindicating a number of client devices that have reported each remoteserver node as unresponsive. For example, remote server nodes that havea flag indicating that no client devices have reported the remote servernode as responsive can have a higher priority. The client device canselect the second remote server node as the available remote server nodewith the highest priority.

The process flow diagram of FIG. 2 is not intended to indicate that theoperations of the method 200 are to be executed in any particular order,or that all of the operations of the method 200 are to be included inevery case. Additionally, the method 200 can include any suitable numberof additional operations. For example, the client device can detect adelete message from the managing server node indicating the requesteddistributed data has been deleted by the remote server node. In someembodiments, the client device can also detect a change to the requesteddistributed data and transmit an update message to the remote serverindicating the change. The update message, as referred to herein, canindicate distributed data returned by a remote server node is outdatedor stale. For example, if a client device receives distributed data froma remote server node, the client device can determine if the distributeddata is current or outdated. In some examples, the update message canresult in the managing server updating distributed data stored in remoteserver nodes.

FIG. 3 is a process flow diagram of an example method that can managedistributed data. The method 300 can be implemented with any suitablecomputing device, such as the managing server 100 of FIG. 1.

At block 302, the message manager 126 can detect an update notificationfrom a client device to update a managing server, the updatenotification indicating that a remote server node is unavailable. Forexample, the client device can detect that a request for distributeddata was not processed within a predetermined threshold period of timesuch as a time to live (TTL) timestamp. The client device can transmitan update notification to the message manager 126 in a managing server,wherein the update notification indicates identifying information for aremote server node that is to be updated in the managing server.

At block 304, the message manager 126 can generate a comparison value bycomparing a first time stamp to a second time stamp, wherein the firsttime stamp corresponds to a time at which the system receives the updatenotification from the client device and the second time stampcorresponds to a time the remote server node transmits a set of renewaldata. In some embodiments, a remote server node can provide a set ofrenewal data at a predetermined rate such as three times a second, orany other suitable frequency. For example, the set of renewal data canindicate identifying information for the remote server node, whichprovides an assurance to the managing server that the remote server nodecan process data requests.

In some embodiments, the message manager 126 can use conflict-freereplicated data types when an external client informs the managingserver via an update notification that a remote server node isunavailable and should be updated in the system. For example, themessage manager 126 can verify that the data received from the clientdevice with time stamp T2, which is equal to a time stamp T1 plus apredetermined value below a threshold, is newer than the current datathe message manager 126 has received from a remote server node, withtime stamp T1. In some embodiments, the message manager 126 compares thetwo time stamps T1 and T2 to determine the data received from the clientdevice is newer than recently received data from a remote server node.In case the message manager 126 received another update from the clientdevice for the same data with time stamp T3, the message manager 126 canverify that T3 is newer than T2 and ignore the data value with the timestamp T2. In some embodiments, there are several options to ensure thatT2 is greater than T1 but smaller than T3. For example, if the messagemanager 126 can detect a minimal interval between two data writecommands or operations, the message manager 126 can set T2 equal to T1plus a value X, such that X is greater than 0 and X is less than aminimal interval between two write commands. In some examples, if themessage manager 126 cannot determine the minimal interval, the messagemanager 126 can detect a client device's identification, the operation,and the timestamp to define a mathematical comparator function. Thecomparator function can indicate that if the two time stamps are equal(T1=T2), the message manager 126 can provide precedence by preferringnon-owner clients for certain operations. For example, updating data byan owner or client device may take precedence over writing data by aremote server node.

At block 306, the server manager 128 can determine that the comparisonvalue indicates the remote server node is unavailable. For example, thecomparison value can indicate that a remote server node has not provideda set of renewal data for a period of time that exceeds a threshold andthe client device has provided an update notification.

At block 308, the server manager 128 can remove the remote server nodefrom the managing server. For example, the server manager 128 can deleteinformation corresponding to the remote server node from the managingserver to prevent additional client devices from attempting to requestdata from the unavailable remote server node. In some examples, theserver manager 128 can delete data from a server database correspondingto the remote server node. For example, the server manager 128 candelete identifying information for a remote server node such as an IPaddress, and the like. In some embodiments, the server manager 128 canremove the remote server node information and store the remote servernode information in a separate list of removed server nodes to bemonitored. For example, network connections can prevent communicationwith a remote server node for a period of time. However, the servermanager 128 can periodically determine if remote server nodes havebecome available again using pinging techniques or any other suitablemethod.

The process flow diagram of FIG. 3 is not intended to indicate that theoperations of the method 300 are to be executed in any particular order,or that all of the operations of the method 300 are to be included inevery case. Additionally, the method 200 can include any suitable numberof additional operations. In some embodiments, the server manager 128can fail the update notification from the client device in response todetermining that the remote server node is unavailable. In someexamples, the message manager 126 can detect the set of renewal data ata predetermined frequency. In some embodiments, the server manager 128can set a flag corresponding to a remote server, wherein the flagindicates that the remote server may not be available. In some examples,the server manager 128 may delete a remote server node from a managingserver in response to a number of client devices indicating that theremote server node is unresponsive.

The present invention may be a system, a method, and/or a computerprogram product. The computer program product may include a computerreadable storage medium (or media) having computer readable programinstructions thereon for causing a processor to carry out aspects of thepresent invention.

The computer readable storage medium can be a tangible device that canretain and store instructions for use by an instruction executiondevice. The computer readable storage medium may be, for example, but isnot limited to, an electronic storage device, a magnetic storage device,an optical storage device, an electromagnetic storage device, asemiconductor storage device, or any suitable combination of theforegoing. A non-exhaustive list of more specific examples of thecomputer readable storage medium includes the following: a portablecomputer diskette, a hard disk, a random access memory (RAM), aread-only memory (ROM), an erasable programmable read-only memory (EPROMor Flash memory), a static random access memory (SRAM), a portablecompact disc read-only memory (CD-ROM), a digital versatile disk (DVD),a memory stick, a floppy disk, a mechanically encoded device such aspunch-cards or raised structures in a groove having instructionsrecorded thereon, and any suitable combination of the foregoing. Acomputer readable storage medium, as used herein, is not to be construedas being transitory signals per se, such as radio waves or other freelypropagating electromagnetic waves, electromagnetic waves propagatingthrough a waveguide or other transmission media (e.g., light pulsespassing through a fiber-optic cable), or electrical signals transmittedthrough a wire.

Computer readable program instructions described herein can bedownloaded to respective computing/processing devices from a computerreadable storage medium or to an external computer or external storagedevice via a network, for example, the Internet, a local area network, awide area network and/or a wireless network. The network may comprisecopper transmission cables, optical transmission fibers, wirelesstransmission, routers, firewalls, switches, gateway computers and/oredge servers. A network adapter card or network interface in eachcomputing/processing device receives computer readable programinstructions from the network and forwards the computer readable programinstructions for storage in a computer readable storage medium withinthe respective computing/processing device.

Computer readable program instructions for carrying out operations ofthe present invention may be assembler instructions,instruction-set-architecture (ISA) instructions, machine instructions,machine dependent instructions, microcode, firmware instructions,state-setting data, or either source code or object code written in anycombination of one or more programming languages, including an objectoriented programming language such as Smalltalk, C++ or the like, andconventional procedural programming languages, such as the “C”programming language or similar programming languages. The computerreadable program instructions may execute entirely on the user'scomputer, partly on the user's computer, as a stand-alone softwarepackage, partly on the user's computer and partly on a remote computeror entirely on the remote computer or server. In the latter scenario,the remote computer may be connected to the user's computer through anytype of network, including a local area network (LAN) or a wide areanetwork (WAN), or the connection may be made to an external computer(for example, through the Internet using an Internet Service Provider).In some embodiments, electronic circuitry including, for example,programmable logic circuitry, field-programmable gate arrays (FPGA), orprogrammable logic arrays (PLA) may execute the computer readableprogram instructions by utilizing state information of the computerreadable program instructions to personalize the electronic circuitry,in order to perform aspects of the present invention.

Aspects of the present invention are described herein with reference toflowchart illustrations and/or block diagrams of methods, apparatus(systems), and computer program products according to embodiments of theinvention. It will be understood that each block of the flowchartillustrations and/or block diagrams, and combinations of blocks in theflowchart illustrations and/or block diagrams, can be implemented bycomputer readable program instructions.

These computer readable program instructions may be provided to aprocessor of a general purpose computer, special purpose computer, orother programmable data processing apparatus to produce a machine, suchthat the instructions, which execute via the processor of the computeror other programmable data processing apparatus, create means forimplementing the functions/acts specified in the flowchart and/or blockdiagram block or blocks. These computer readable program instructionsmay also be stored in a computer readable storage medium that can directa computer, a programmable data processing apparatus, and/or otherdevices to function in a particular manner, such that the computerreadable storage medium having instructions stored therein comprises anarticle of manufacture including instructions which implement aspects ofthe function/act specified in the flowchart and/or block diagram blockor blocks.

The computer readable program instructions may also be loaded onto acomputer, other programmable data processing apparatus, or other deviceto cause a series of operational steps to be performed on the computer,other programmable apparatus or other device to produce a computerimplemented process, such that the instructions which execute on thecomputer, other programmable apparatus, or other device implement thefunctions/acts specified in the flowchart and/or block diagram block orblocks.

The flowchart and block diagrams in the Figures illustrate thearchitecture, functionality, and operation of possible implementationsof systems, methods, and computer program products according to variousembodiments of the present invention. In this regard, each block in theflowchart or block diagrams may represent a module, segment, or portionof instructions, which comprises one or more executable instructions forimplementing the specified logical functions. In some alternativeimplementations, the functions noted in the block may occur out of theorder noted in the figures. For example, two blocks shown in successionmay, in fact, be executed substantially concurrently, or the blocks maysometimes be executed in the reverse order, depending upon thefunctionality involved. It will also be noted that each block of theblock diagrams and/or flowchart illustration, and combinations of blocksin the block diagrams and/or flowchart illustration, can be implementedby special purpose hardware-based systems that perform the specifiedfunctions or acts or carry out combinations of special purpose hardwareand computer instructions.

Referring now to FIG. 4, a block diagram is depicted of an example of atangible, non-transitory computer-readable medium that can managedistributed data. The tangible, non-transitory, computer-readable medium400 may be accessed by a processor 402 over a computer interconnect 404.Furthermore, the tangible, non-transitory, computer-readable medium 400may include code to direct the processor 402 to perform the operationsof the current method. For example, a message manager 406 can detect anupdate notification from a client device to update a managing server,the update notification indicating that a remote server node isunavailable. The message manager 406 can also generate a comparisonvalue by comparing a first time stamp to a second time stamp, whereinthe first time stamp corresponds to a time at which the system receivesthe update notification from the client device and the second time stampcorresponds to a time the remote server node transmits a set of renewaldata. Furthermore, a server manager 410 can determine that thecomparison value indicates the remote server node is unavailable andremove the remote server node from the managing server.

It is to be understood that any number of additional software componentsnot shown in FIG. 4 may be included within the tangible, non-transitory,computer-readable medium 400, depending on the specific application.Furthermore, fewer software components than those shown in FIG. 4 can beincluded in the tangible, non-transitory, computer-readable medium 400.

Referring now to FIG. 5, a block diagram is depicted of an example of atangible, non-transitory computer-readable medium that can managedistributed data. The tangible, non-transitory, computer-readable medium500 may be accessed by a processor 502 over a computer interconnect 504.Furthermore, the tangible, non-transitory, computer-readable medium 500may include code to direct the processor 502 to perform the operationsof the current method. For example, a client manager 506 can send arequest for distributed data to a remote server node and detect that aperiod of time elapses without receiving the distributed data from theremote server node. The client manager 506 can also update a managingserver by sending a server message to the managing server indicatingthat the remote server node is unavailable and send the request for thedistributed data to a second remote server node.

It is to be understood that any number of additional software componentsnot shown in FIG. 5 may be included within the tangible, non-transitory,computer-readable medium 500, depending on the specific application.

Referring now to FIG. 6, illustrative cloud computing environment 600 isdepicted. As shown, cloud computing environment 600 comprises one ormore cloud computing nodes 602 with which local computing devices usedby cloud consumers, such as, for example, personal digital assistant(PDA) or cellular telephone 604A, desktop computer 604B, laptop computer604C, and/or automobile computer system 604N may communicate. Nodes 602may communicate with one another. They may be grouped (not shown)physically or virtually, in one or more networks, such as Private,Community, Public, or Hybrid clouds as described hereinabove, or acombination thereof. This allows cloud computing environment 600 tooffer infrastructure, platforms and/or software as services for which acloud consumer does not need to maintain resources on a local computingdevice. It is understood that the types of computing devices 604A-Nshown in FIG. 6 are intended to be illustrative only and that computingnodes 602 and cloud computing environment 600 can communicate with anytype of computerized device over any type of network and/or networkaddressable connection (e.g., using a web browser).

Referring now to FIG. 7, a set of functional abstraction layers providedby cloud computing environment 600 (FIG. 6) is shown. It should beunderstood in advance that the components, layers, and functions shownin FIG. 7 are intended to be illustrative only and embodiments of theinvention are not limited thereto. As depicted, the following layers andcorresponding functions are provided.

Hardware and software layer 700 includes hardware and softwarecomponents. Examples of hardware components include mainframes, in oneexample IBM® zSeries® systems; RISC (Reduced Instruction Set Computer)architecture based servers, in one example IBM pSeries® systems; IBMxSeries® systems; IBM BladeCenter® systems; storage devices; networksand networking components. Examples of software components includenetwork application server software, in one example IBM WebSphere®application server software; and database software, in one example IBMDB2® database software. (IBM, zSeries, pSeries, xSeries, BladeCenter,WebSphere, and DB2 are trademarks of International Business MachinesCorporation registered in many jurisdictions worldwide).

Virtualization layer 702 provides an abstraction layer from which thefollowing examples of virtual entities may be provided: virtual servers;virtual storage; virtual networks, including virtual private networks;virtual applications and operating systems; and virtual clients. In oneexample, management layer 704 may provide the functions described below.Resource provisioning provides dynamic procurement of computingresources and other resources that are utilized to perform tasks withinthe cloud computing environment. Metering and Pricing provide costtracking as resources are utilized within the cloud computingenvironment, and billing or invoicing for consumption of theseresources. In one example, these resources may comprise applicationsoftware licenses. Security provides identity verification for cloudconsumers and tasks, as well as protection for data and other resources.User portal provides access to the cloud computing environment forconsumers and system administrators. Service level management providescloud computing resource allocation and management such that requiredservice levels are met. Service Level Agreement (SLA) planning andfulfillment provide pre-arrangement for, and procurement of, cloudcomputing resources for which a future requirement is anticipated inaccordance with an SLA.

Workloads layer 706 provides examples of functionality for which thecloud computing environment may be utilized. Examples of workloads andfunctions which may be provided from this layer include: mapping andnavigation; software development and lifecycle management; virtualclassroom education delivery; data analytics processing; transactionprocessing; and managing distributed data.

The descriptions of the various embodiments of the present inventionhave been presented for purposes of illustration, but are not intendedto be exhaustive or limited to the embodiments disclosed. Manymodifications and variations will be apparent to those of ordinary skillin the art without departing from the scope and spirit of the describedembodiments. The terminology used herein was chosen to best explain theprinciples of the embodiments, the practical application or technicalimprovement over technologies found in the marketplace, or to enableothers of ordinary skill in the art to understand the embodimentsdisclosed herein.

What is claimed is:
 1. A system for managing distributed datacomprising: a processor to: send a distributed data request to a remoteserver node; detect that a period of time elapses without receiving therequested distributed data from the remote server node; update amanaging server by sending a server message to the managing serverindicating that the remote server node is unavailable; and send thedistributed data request to a second remote server node.
 2. The systemof claim 1, wherein the system is a consumer client that is to send thedistributed data request to the remote server node via the managingserver.
 3. The system of claim 1, wherein the system is to monitorwhether the remote server node and the second remote server node areavailable.
 4. The system of claim 1, wherein the distributed datacorresponds to a service provided by the remote server node.
 5. Thesystem of claim 1, wherein the server message indicates an internetprotocol address corresponding to the remote server node.
 6. The systemof claim 1, wherein the processor is to detect a delete message from themanaging server node indicating the requested distributed data has beendeleted by the remote server node.
 7. The system of claim 1, wherein theprocessor is to detect a change to the requested distributed data andtransmit an update message to the remote server indicating the change.8. A system for managing distributed data comprising: a processor to:detect an update notification from a client device to update a managingserver, the update notification indicating that a remote server node isunavailable; generate a comparison value by comparing a first time stampto a second time stamp, wherein the first time stamp corresponds to atime at which the system receives the update notification from theclient device and the second time stamp corresponds to a time the remoteserver node transmits a set of renewal data; determine that thecomparison value indicates the remote server node is unavailable; andremove the remote server node from the managing server.
 9. The system ofclaim 8, wherein the managing server comprises an internet protocoladdress for a set of remote server nodes.
 10. The system of claim 8,wherein the processor is to identify a second remote server node from apredetermined list.
 11. The system of claim 10, wherein the processor isto determine the second remote server node in response to querying themanaging server for the second remote server node.
 12. The system ofclaim 8, wherein the processor is to remove the remote server node is toprevent additional client devices from attempting to access the remoteserver node.
 13. The system of claim 8, wherein the processor is to failthe update notification from the client device in response todetermining that the remote server node is unavailable.
 14. The systemof claim 8, wherein the processor is to detect the set of renewal dataat a predetermined frequency.
 15. The system of claim 8, wherein themanaging server comprises a database comprising identifying informationfor a plurality of remote server nodes.
 16. A computer program productfor managing distributed data, the computer program product comprising acomputer readable storage medium having program instructions embodiedtherewith, wherein the computer readable storage medium is not atransitory signal per se, the program instructions executable by aprocessor to cause the processor to: detect an update notification froma client device to update a managing server, the update notificationindicating that a remote server node is unavailable; generate acomparison value by comparing a first time stamp to a second time stamp,wherein the first time stamp corresponds to a time at which the systemreceives the update notification from the client device and the secondtime stamp corresponds to a time the remote server node transmits a setof renewal data; determine that the comparison value indicates theremote server node is unavailable; and remove the remote server nodefrom the managing server.
 17. The computer program product of claim 16,wherein the program instructions cause the processor to identify asecond remote server node from a predetermined list.
 18. The computerprogram product of claim 17, wherein the program instructions cause theprocessor to determine the second remote server node in response toquerying the managing server for the second remote server node.
 19. Thecomputer program product of claim 16, wherein the managing servercomprises an internet protocol address for a set of remote server nodes.20. The computer program product of claim 16, wherein the programinstructions cause the processor to detect the set of renewal data at apredetermined frequency.